(1) Field of the Invention
This invention relates to cutter tools and to methods of grinding the cutters of such cutter tools.
In particular the invention is concerned with groove cutting tools such as rotary saws, or other cutter tools having a line of cutter teeth.
(2) Description of the Prior Art
In the case of a rotary saw this essentially includes a circular body with an arbor receiving bore and a plurality of regularly spaced radially directed teeth at the periphery of the body. The teeth are shaped to provide a cutting edge located in advance of the remainder of the tooth in the direction of advance of the tooth into a workpiece. Each such tooth is usually provided with a cutting tip of a harder material than the remainder of the blade. These tips are made of a variety of materials such as cobalt steel alloys, tungsten carbide or other materials. The tips are usually brazed or otherwise similarly secured to the associated tooth.
For the purposes of convenience the following description will be directed to rotary saws having a tip on every tooth, even though in some cases tips are provided on some of the teeth and not all.
Furthermore the principles of the invention to be discussed hereinafter could be applied to saws such as band saws, reciprocating machine actuated saws, hand saws and the like.
Various proposals have been made to provide hard tips on a cutter tooth. However, with the known proposals it has been found that when rotary saw blades having the known tip formations are rotated at high speeds, for example, at speeds having a peripheral speed of 40 to 70 meters per second, excessive noise levels are produced which create unacceptable operator working conditions. A particular form taken by the blade noise is a whistling sound which, depending upon factors such as the rotational speed of the blade, develops noise concentrations at various frequencies. It is thought that a possible source of the noise resides in vibrations arising from air pressure conditions within the gullets of the blade. In addition, as a direct consequence of inherent design and manufacturing factors the blade can be set into a sustained vibration so that the blade starts to ring, for example, like a bell.
It is an object of the invention to provide an improved cutter tool and methods for making such tools.